wehub-resource-sync
127 lines
4.0 KiB
Go
127 lines
4.0 KiB
Go
// Copyright 2024 Dolthub, Inc.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
package functions
|
|
|
|
import (
|
|
"math"
|
|
|
|
"github.com/cockroachdb/apd/v3"
|
|
"github.com/cockroachdb/errors"
|
|
"github.com/dolthub/go-mysql-server/sql"
|
|
"github.com/dolthub/go-mysql-server/sql/types"
|
|
|
|
"github.com/dolthub/doltgresql/server/functions/framework"
|
|
pgtypes "github.com/dolthub/doltgresql/server/types"
|
|
)
|
|
|
|
// initPower registers the functions to the catalog.
|
|
func initPower() {
|
|
framework.RegisterFunction(power_float64_float64)
|
|
framework.RegisterFunction(power_numeric_numeric)
|
|
}
|
|
|
|
var (
|
|
// errPowerZeroToNegative is an error for raising zero to a negative power in the "power" functions.
|
|
errPowerZeroToNegative = errors.New("zero raised to a negative power is undefined")
|
|
// numericOne is equivalent to apt.NewFromInt(1, 0), but represented as a value for the sake of efficiency.
|
|
numericOne = apd.New(1, 0)
|
|
)
|
|
|
|
// power_float64_float64 represents the PostgreSQL function of the same name, taking the same parameters.
|
|
var power_float64_float64 = framework.Function2{
|
|
Name: "power",
|
|
Return: pgtypes.Float64,
|
|
Parameters: [2]*pgtypes.DoltgresType{pgtypes.Float64, pgtypes.Float64},
|
|
Strict: true,
|
|
Callable: func(ctx *sql.Context, _ [3]*pgtypes.DoltgresType, val1 any, val2 any) (any, error) {
|
|
f1 := val1.(float64)
|
|
f2 := val2.(float64)
|
|
if f1 == 0 && f2 < 0 {
|
|
return nil, errPowerZeroToNegative
|
|
}
|
|
return math.Pow(f1, f2), nil
|
|
},
|
|
}
|
|
|
|
// power_numeric_numeric represents the PostgreSQL function of the same name, taking the same parameters.
|
|
var power_numeric_numeric = framework.Function2{
|
|
Name: "power",
|
|
Return: pgtypes.Numeric,
|
|
Parameters: [2]*pgtypes.DoltgresType{pgtypes.Numeric, pgtypes.Numeric},
|
|
Strict: true,
|
|
Callable: func(ctx *sql.Context, _ [3]*pgtypes.DoltgresType, val1 any, val2 any) (any, error) {
|
|
dec1 := val1.(*apd.Decimal)
|
|
dec2 := val2.(*apd.Decimal)
|
|
if dec1.Form == apd.NaN || dec2.Form == apd.NaN {
|
|
return pgtypes.NumericNaN, nil
|
|
}
|
|
if dec1.Form == apd.Infinite && dec1.Negative {
|
|
// dec1 is -Infinity
|
|
even := dec2.Form == apd.Infinite && !dec2.Negative
|
|
if dec2.Form == apd.Finite {
|
|
i, err := dec2.Int64()
|
|
if err != nil {
|
|
return nil, errors.Errorf(`a negative number raised to a non-integer power yields a complex result`)
|
|
}
|
|
even = i%2 == 0
|
|
}
|
|
if dec2.Sign() > 0 {
|
|
// +inf will return neginf == fix!!
|
|
if even {
|
|
return pgtypes.NumericInf, nil
|
|
}
|
|
return pgtypes.NumericNegInf, nil
|
|
}
|
|
if (dec2.Form == apd.Infinite && dec2.Negative) || dec2.Sign() < 0 {
|
|
return apd.New(0, 0), nil
|
|
}
|
|
return apd.New(1, 0), nil
|
|
} else if dec1.Form == apd.Infinite {
|
|
// dec1 is +Infinity
|
|
d2Sign := dec2.Sign()
|
|
if dec2.Sign() < 0 {
|
|
return apd.New(0, 0), nil
|
|
} else if d2Sign == 0 {
|
|
return apd.New(1, 0), nil
|
|
}
|
|
return types.DecimalPosInf, nil
|
|
} else if dec1.IsZero() {
|
|
// dec1 is 0
|
|
if dec2.Sign() < 0 {
|
|
// includes neg inf
|
|
return nil, errPowerZeroToNegative
|
|
}
|
|
if dec2.Form == apd.Infinite {
|
|
return apd.New(0, 0), nil
|
|
}
|
|
if dec2.Sign() > 0 {
|
|
return sql.DecimalRound(apd.New(0, 0), 16)
|
|
}
|
|
}
|
|
// decimal.Pow() does not handle the zero exponent properly, so we special case it
|
|
if dec2.IsZero() || dec1.Cmp(numericOne) == 0 {
|
|
return sql.DecimalRound(apd.New(1, 0), 16)
|
|
}
|
|
|
|
// give enough precision that we can round it to 16 exp
|
|
res := new(apd.Decimal)
|
|
_, err := sql.DecimalCtx.WithPrecision(17).Pow(res, dec1, dec2)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return sql.DecimalRound(res, 16)
|
|
},
|
|
}
|